Histologic and Cell Kinetic Studies of Hair Loss and Subsequent Recovery Process of Human Scalp Hair Follicles Grafted onto Severe Combined Immunodeficient Mice
August 2000
in “
Journal of Investigative Dermatology
”
hair follicles severe combined immunodeficient mice dystrophic stage regeneration stage stable growth stage apoptosis keratin 19-positive cells keratin 19-negative cells BrdU-labeled cells inner root sheath hair shaft anagen hair follicles melanin incontinence stem cells secondary germ SCID mice BrdU
TLDR Stem cells are key for hair follicle recovery.
The study examined human scalp hair follicles grafted onto severe combined immunodeficient (SCID) mice, observing distinct stages of hair loss and recovery: dystrophic (days 7-30), regeneration (days 30-50), and stable growth (days 40-150). Initially, follicles became dystrophic and shed hair, with apoptosis and regression. During regeneration, keratin 19-positive cells were replaced by keratin 19-negative and BrdU-labeled cells, leading to differentiation into an inner root sheath and hair shaft. By the stable growth stage, follicles resembled normal anagen hair follicles, except for melanin incontinence. The study concluded that stem cells or their progeny in the secondary germ were crucial for follicle recovery, and the model was useful for studying human hair follicle morphology and recovery.
